That was published in 1984 covering a multiband affair. According to Heys, G3BDQ, the original G5RV article was published in 1946 for a single band antenna. In fact the biography box on the first page of the linked article says Varney designed the original G5RV in 1946.
Varney published several articles about multiband use of his design. There's an update of the article linked below, also by Varney, available on the ARRL web site (www.arrl.org). Varney simply reverted to using his design as a center fed doublet on any band except 20 meters! Of course, a center-fed doublet (random length horizontal wire, broken at the center for low-loss open-wire feedline) has been an well-known, efficient antenna since the 1920's. Varney offered nothing new in his G5RV design except on 20 meters where the length of the horizontal wire coupled with the matching section (33 feet of open wire line of specific size and spacing) produced a tolerably low SWR for common types of feed lines in use in 1946. It needed a matching network between the feedline and the matching section on other bands, and was not optimized for 50 ohm coax even on 20 meters! From the referenced article, Varney writes: "Although the impedance match for 75-ohm twin lead or 80-ohm coaxial cable at the base of the matching section is good at 14 MHz, and even the use of 50 ohm coaxial cable results in only about a 1.8:1 SWR on this band, the use of a suitable matching network is necessary on all other HF bands.." Note the terminology: "Matching section" is the length of open wire line of specific length, wire size and spacing used to match the center of the horizontal wire to a feed line at the lower end. "Matching network" is what we call today an antenna tuner or ATU. The matching network (ATU) should be at the end of the matching section (open work line), not at the rig. Putting the tuner at the rig adds significant losses to the system depending upon the type and length of feeder used between the rig and the "matching section". Also, note that the original design was optimized for 80 ohm coax or 75 ohm twinlead, both of which were fairly common right after WWII. Post WWII rigs with tunable "pi-network" outputs could handle quite a wide range of feeder impedances efficiently without resorting to an external "tuner". We weren't particularly concerned about an SWR of 2:1, 4:1 or more even if we had the means to measure it. So a 1.8:1 SWR was quite good. Of course, with today's fixed-tuned rigs that's crowding the point at which the rig will roll back power or shut down altogether to protect the finals unless a tuner is used at the output to reduce the SWR the rig "sees". Used that way, the G5RV is identical to the common multi-band doublet used since the 1920's. It's efficient if: 1) An efficient tuner is used capable of matching the rig to the antenna, and 2) No coax or other lossy feed line is used between the tuner and the radiator. Bottom line is that the practice of putting the tuner at the rig, and running coax between the tuner and the radiator with perhaps a balun or unun thrown in significantly increases the losses. Ron AC7AC -----Original Message----- Ref question N2EY You will find the original article from G5RV himself on: www.remeeus.eu/hamradio/antennes_tuners/g5rv.htm 73, Rob, PA0RBO, K2 # 2406 _______________________________________________ _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
